1. Field of the Invention
The present invention relates to a fuel supply system for internal combustion engines which has an improved fuel leakage restricting structure.
2. Related Art
A cylinder direct injection type fuel supply system has been proposed for an automotive vehicle gasoline internal combustion engine as shown in FIG. 6A, to improve engine efficiency for environmental protection. In this system, a fuel delivery pipe 1 is connected to a high pressure fuel pump (not shown) via a fuel pipe 2. A fuel injector 4 for each cylinder is mounted on an engine cylinder head 5 so that fuel is directly injected into a combustion chamber. The injector 4 is coupled with the delivery pipe 1 via a rubber sealing member such as an O-ring 3. A high pressure fuel injection is attained by the injector 4 to improve fuel spray atomization. It is important to ensure sealing property in the fuel supply system.
The rubber sealing member 3 fitted between the delivery pipe 1 and the injector 4 tends to change its sealing characteristics largely depending on changes in surrounding temperature. Further, the delivery pipe 1 bows in response to the high fuel pressure by an amount of flexing .delta. as shown in FIG. 6(B). As a result, use of the rubber sealing member 3 is limited by surrounding conditions (fuel pressure, temperature, etc.).